葡萄酒的低场核磁共振弛豫谱

 低场¹H-核磁共振弛豫可以有效地测量食品中水分、油脂和酒精等组分，葡萄酒中水O-H基和乙醇C-H基是产生共振弛豫谱的物理基础。采用CPMG方法和反转—恢复技术分别得到葡萄酒核磁共振横向弛豫和纵向弛豫曲线，并使用连续谱迭代方法与离散谱拟合分析获得核磁共振弛豫谱。通过添加去离子水或95%食用酒精配制不同酒精含量样品，由谱峰面积占比变化确定弛豫谱峰的归属。研究发现，T₂ 谱中弛豫时间较长的谱峰反映了酒精的含量，且其峰面积占比随酒精体积浓度变化呈线性递增关系。随机抽样的实验结果表明，¹H-核磁共振弛豫谱具有普适性，从而可建立基于T₂ 谱的葡萄酒酒精度测量技术。

Low-Field NMR Relaxation Spectrum of Wine

As low field ¹H-NMR relaxation can effectively measure water, fat and alcohol content in foods, O-H in water and C-H in alcohol are the physical basic for resonance relaxation spectrum of wine. CPMG and inversion-recovery technique were applied to respectively obtain the transverse relaxation and longitudinal relaxation of the wine samples, and then the resonance relaxation spectrum was acquired by the continuous spectrum iteration as well as discrete spectrum fitting analysis. The samples were treated into certain proportions by adding deionized water or 95% edible alcohol. According to the variation of peak area ratio, the assignments of two relaxation peaks were determined. The study found that in transverse relaxation spectrum, the peak with a longer relaxation time reflected the alcohol content, and its area proportion had a positive linear correlation with alcohol concentration. In addition, random samples verified the universality of resonance relaxation spectrum and therefore, based on T₂ spectrum, a new measuring technique for wine alcohol content can be built up.